1. Field of the Invention
This invention relates to the use and application of a common purpose apparatus that enables the physical and chemical processing as well as thermo chemical transformation of carbonaceous materials including but not limited to drying, pyrolysis, gasification, staged combustion, uniform combustion, destruction of hazardous contaminants, and the production of bio-char. The apparatus of this invention is able to process all types of solid, liquid, and gaseous carbonaceous materials including but not limited to agriculture and forestry products and wastes; solid, liquid, and gaseous industry wastes, municipal solid wastes; sewage sludge; coal; oil shale; petroleum refinery residues; and hazardous wastes processed individually or as mixtures without limitation on source of these materials and without limitations on their physical nature or physical characteristics.
2. General Background and State of the Art
The general background and the state of the art included in the applications US application publication numbers 2014/0202079, filed Jan. 22, 2013 and 2013/0119315, filed Jan. 3, 2013, are incorporated herein by reference and additional information is added in order to further distinguish the versatility of the present invention over the present art of physical and chemical processing of the carbonaceous materials as well as that of thermochemical transformation of carbonaceous materials.
The types of apparatus commonly employed for physical and chemical processing include fluidized bed reactors, entrained bed reactors, fixed bed reactors, moving bed reactors, and rotary kiln reactor. Each one of these present arts have limited applications with respect to physical and chemical processing and with respect to thermochemical transformation of carbonaceous materials because of their restrictive covenants with respect to the physical and chemical properties of the carbonaceous materials and as well as due to physical limitations of these types of apparatus themselves.
A fluidized bed apparatus, for example, has limited application for general purposes achieved by this patent since it has to be designed differently for each specific application of physical or chemical processing as well as for thermochemical transformation reactions for similar carbonaceous materials. The design has to be precise with respect to the application of drying, pyrolysis, gasification, or combustion and has then to remain restricted for that specific use or application. The design of the system is also dictated and then to remain restricted by the physical characteristics of the material being processed especially with respect to density, size, and uniformity of the individual particles of the material. Once designed for one application and one type of material, the apparatus has no flexibility with respect to changing of application or with respect to changing physical nature of the carbonaceous material being processed or with combining varied source carbonaceous materials of vastly different physical and chemical properties. For example, changing the application of carbonaceous material being processed for gasification to the application of combustion would require three to four times the original gas reactant which will increase to gas velocity in the fluidized bed beyond its limitation and thereby cause upset in the reactor resulting in incomplete or inadequate processing.
As another example, the entrained bed reactor is specifically designed to keep the carbonaceous material in the stream of gas, which is accomplished by making the carbonaceous material very small in size. The reactor is designed such that the mixture of gas and solid particles passing through the predetermined sized reactor remain in intimate contact and attain certain conversion of the carbonaceous material, be it gasification or combustion mode of application. A change in physical size of the carbonaceous material or a change in density of the carbonaceous material would completely alter the dynamics of the reactor and would no longer yield the intended results of the application. Larger particles and or denser particles will segregate since the prescribed velocity of the gas will no longer be able to carry the larger and heavier particles. Trying to adjust the gas velocity to accommodate the larger or the heavier particles will result in gas and solids spending lesser time inside the reactor and result in incomplete or inadequate processing of the carbonaceous material.
As another example, the downdraft reactor is sensitive to the density of the carbonaceous material being processed as well as to the uniformity of the said material. This reactor is also not easily adaptable to changing applications for example from gasification to combustion since the increased amount of reactant gases to accomplish combustion would generate pockets of hot spots within the reactor which will result in the agglomeration of materials and result in abortion of the operation.
Similarly, the conventional rotary kiln differs significantly from the present invention because of its limited applications. The conventional rotary kiln is suitable for conventional combustion of carbonaceous material. For combustion application, more than stoichiometric amount of oxidant is introduced simultaneously with the carbonaceous material to instantly combust volatile fraction as well as fixed carbon portion of the carbonaceous materials. However, when the same kiln reactor is used for gasification applications requiring reaction with sub-stoichiometric amounts of oxidant, the conversion results are dismal. This is because when the carbonaceous material and sub-stoichiometric amount of air are introduced into the kiln reactor simultaneously, the limited amount of oxidant prefers to react with the combustible gases that are generated first from the devolatalization of the carbonaceous material rather than with the remaining carbon in the partially reacted carbonaceous material. Hence, mere switching from combustion to gasification mode using conventional kiln reactor does not function optimally when used for both applications. In reality, industry has recognized that a conventional kiln is not suitable for carrying out the gasification of the carbonaceous materials.
In general all industries require many of the unit operations including drying, combustion, gasification, and hazardous waste treatment at one time or another. Good example of this is a chemical plant which may need to remediate soil after an oil spill and at times might find it advantageous to harness energy from the waste materials that it produces, both of which involve widely different unit operations that would normally require having at its site two different sets of apparatus. These two operations are contrasted by large range of operating conditions with regards to temperature, gas solid interactions, amount of gas handled, type of material handled, residence time requirements for complete destruction of organics, and the method by which the energy is ultimately recovered. Having to require different systems for each of these applications is neither practical nor cost effective. When myriads of such industries are considered requiring hundreds of different unit operations that at times require in short span physical, thermal, and thermo-chemical processing unit operations, there is clearly a need for a single common purpose apparatus that would operate and function within many of these contrasting ranges of operating conditions and requiring widely different operating results. The present invention clearly meets this demand.
In contrast to all the current arts, the present invention provides a versatile apparatus that accommodates multitude of physical and chemical processing of carbonaceous materials as well as thermo chemical transformation of carbonaceous materials. This is accomplished through systematic introduction of reactant gases into the reactor assembly that provides effective gas solid reactions within the prescribed unit operations for the application of drying, pyrolysis, gasification, staged combustion, uniform combustion, destruction of hazardous contaminants, and production of bio-char with freedom of instant interchangeability with respect to the application and without regard to physical properties and characteristics of the carbonaceous materials including size and density as well as without regard to their chemical compositions resulting from switching the source or combining the sources of the carbonaceous materials. The present invention also incorporates provision for additional thermal treatment of gaseous products of reactions from all applications and allows for handling of different gas volumes arising from different applications. In addition to gas distribution along the length of the reactor, the present invention also provides for gas-solid contacting along the circumference of the reactor wall to coincide with the position of solids along the circumference, which is mainly dictated by the changing speed of the rotation of the kiln reactor. The flexibility of the apparatus accorded by the present invention permits broad range of unit operations without limitation, and hence it will find use in broad range of industries including power generation, chemical and process industries, agriculture waste processing, and oil refining, as well for energy recovery from municipal solid and other types of wastes and for remediation of hazardous wastes.